Greetings Retouchers,
The 8x8 pixel squares are created from the jpeg compression algorithim. What they're doing is averaging data in the 8x8 square (actually, they're nested 8x8 squares inside 16x16 squares). As long as you keep saving it as a JPEG it will keep producing these squares. Save it as a
TIF file to keep all the pixel data as scanned. The problem will be, of course, uploading it to the web since it will be humongous. Scanning it at 300 lpi(dpi) should be more than sufficient.
Descreening is only useful if the source image is from a printed page like a magazine or newspaper. Descreening cuts down on the moire effect that digitizing these sources can create.
Flora, you are simply amazing.

Would love to know how you did that.